Disc brake unit



FIG. 1 is a front view showing my new design for a disc brake unit;

FIG. 2 is a left side view thereof,

FIG. 3 is a right side view thereof,

FIG. 4 is a top view thereof,

FIG. 5 is a bottom view thereof; and,

FIG. 6 is a rear view thereof. 

The ornamental design for a disc brake unit, as shown and described. 